Iron‐Catalyzed Anti‐Markovnikov Hydroamination of Vinylpyridines

Abstract

An efficient, green and atom-economical ironcatalyzed hydroamination of vinylpyridines with azoles has been developed. This reaction works smoothly for adiverse range of vinylpyridines and azoles, including diazoles and triazoles. The reactionw as catalyzed by 5mol % FeCl 3 in toluene at 110 8Cf or 3h to afford the anti-Markovnikov hydroaminationp roductsi nm oderate to excellent yields and excellent selectivities.Scheme1.Catalytic anti-Markovnikov hydroamination of vinylpyridines.

Earth-Abundant 3d Transition Metal Catalysts for Hydroalkoxylation and Hydroamination of Unactivated Alkenes

“…Recently, C-N bond formation by hydroamination of unactivated alkenes with unbiased amines has also been described with iron(III) salts as Lewis acid catalysts. An interesting anti-Markovnikov hydroamination of vinylpyridines with azoles including diazoles and triazoles, catalyzed by FeCl 3 was recently reported (Figure 6, top) [62]. The reaction proceeded at 110 • C and gave moderate-to-excellent yields.…”

Anti-Markovnikov Intermolecular Hydroamination of Alkenes and Alkynes: A Mechanistic View

“…In 2017, Li, Wang, and co-workers published a Fe(III)-catalyzed hydroamination of vinylpyridines with azoles (Table 7, entry 17). 167 The reaction is catalyzed by FeCl 3 (5 mol % Fe-1) in toluene at 110 °C, affording the anti-Markovnikov product in excellent regioselectivities and moderate to excellent yields in short reaction times (3 h). Once the reaction conditions were optimized (1.5 mmol 2-vinylpyridine; 1.0 mmol benzotriazole; 0.05 mmol FeCl 3 ), they investigated the scope of both reactants, vinylpyridines and azoles.…”

“…In 2017, Li, Wang, and co-workers published a Fe­(III)-catalyzed hydroamination of vinylpyridines with azoles (Table , entry 17) . The reaction is catalyzed by FeCl 3 (5 mol % Fe-1 ) in toluene at 110 °C, affording the anti-Markovnikov product in excellent regioselectivities and moderate to excellent yields in short reaction times (3 h).…”

“…Iron. The proposed mechanism for the Fe-catalyzed hydroamination reaction of vinylpyridines with azoles (Table , entry 17) is shown in Scheme . The first step is the coordination of the 2-vinylpyridine to the FeCl 3 by means of the N atom.…”

“…The proposed mechanism for the Fecatalyzed hydroamination reaction of vinylpyridines with azoles (Table 7, entry 17) is shown in Scheme 58. 167 The first step is the coordination of the 2-vinylpyridine to the FeCl 3 by means of the N atom. The complex formed leads to a polarized zwitterionic intermediate with a formal positive charge on the N atom; by resonance, this charge can be located at the terminal carbon atom of the vinyl group.…”